Pile driver

ABSTRACT

A pile driver characterized by pile-holding chucks being suspended from the top bed subjected to the oil pressure of a hydraulic cylinder in such a way that the chucks may be brought up to or separated from the top bed; a spring and a cam for stretching or compressing the spring being inserted between the top bed and the chucks; and the downward oil pressure (static load) applied to the top bed being transformed into a dynamic load through expansion and contraction of the spring, to be transmitted to the chucks. With use of the dynamic load the piles can be driven fast without developing noise.

United States Patent [1 1 Majima [4 1 Mar. 18, 1975 PILE DRIVER [76] Inventor: Keiichiro Majima, 1380-2 Nishitoyoi, Kudamatsu, Japan [22] Filed: June 28, 1973 [211 App]. No.: 374,382

[30] Foreign Application Priority Data May 18, I973 Japan 48-55329 [52] U.S. Cl 254/29 R, 6|/53.5, 74/55, l73/l23, 404/133 [5|] Int. Cl. E021! 7/18, B06b l/IO [58] Field of Search 254/29 R; 60/369; 61/535; 64/27 CS; l73/l23; 74/55; 404/133 3,003,747 l0/l96l Thomas i. 254/29 R 3.004389 l0/l961 Muller 254/29 R 3,477,237 ll/l969 Orkney til/53.5

Primary Examiner-Al Lawrence Smith Assistant Examiner-Robert C. Watson Attorney, Agent, or Firm-Connolly and Hutz [57] ABSTRACT A pile driver characterized by pile-holding chucks being suspended from the top bed subjected to the oil pressure ofa hydraulic cylinder in such a way that the chucks may be brought up to or separated from the top bed; a spring and a cam for stretching or compressing the spring being inserted between the top bed and the chucks; and the downward oil pressure (static load) applied to the top bed being transformed into a dynamic load through expansion and contraction of the spring, to be transmitted to the chucks. With use of the dynamic load the piles can be driven fast without developing noise.

6 Claims, 4 Drawing Figures PATENTEUHW 81% 3.87 1.617

SHEET 2 [If 3 FIG.2

FILE DRIVER SUMMARY OF THE INVENTION The present invention relates to a pile driver utilizing oil pressure, more specifically to a pile driver characterized by the fact that the static load obtained by the oil pressure is mechanically converted to a dynamic load, which is then transmitted to the pile.

Drop-hammer and others are known as the conventional means for driving piles such as concrete piles and sheet piles into the ground, but they have drawbacks in that they produce considerable noise in their working or they take much time for driving the piles.

The object of the present invention is therefore, to provide a pile driver which can do the job swiftly with no noise.

Another object of the present invention is to provide a pile driver which can drive a new sheet pile along the one already driven in, when sheet piles are to be driven in succession.

Still another object of the present invention is to provide a pile driver which can drive piles at varied positions within certain limits relative to the foundation. To attain these objects, the present invention is fundamentally constituted such that the rod of a vertically installed hydraulic cylinder is connected to the top bed; chucks are suspended from this top bed, movably close to or far from said top bed; between the top bed and the chucks a spring and a cam for stretching or compressing the spring are inserted; and the rotation of the cam causes the spring to be stretched or compressed. Further, to make it possible to change the pile-driving position within certain limits relative to the foundation, the above constitution is made on a slide bed which is horizontally shiftable in relation to the foundation. Meanwhile. to make it possible to drive a new sheet pile along the one already driven into the ground, the chucks are installed near-horizontally movable relative to the top bed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side-sectional view of the essential parts of an embodiment of the present invention;

FIG. 2 is a plan view of the embodiment of FIG. 1;

FIG. 3 is a sectional view taken along the line III-III in FIG. 1 which mainly shows the plan of an embodiment of the cam drive mechanism;

FIG. 4 is a schematic view illustrating an embodiment of the chucks.

DETAILED DESCRIPTION OF THE INVENTION Referring to the illustrated embodiment, the present invention is to be described below.

In FIGS. 1 and 2, l is a foundation equipped with a travelling device such as caterpillar. Upon the founda tion are fixed rails 3, 3 of a T-section, extending in such a direction as intersects the moving direction of foundation l and when foundation 1 is placed, a slide bed 4 slides along rails 3, 3. Thus, slide bed 4 is slidable at right angles to the travel of foundation 1, but it never leaves foundation 1. At the four corners of slide bed 4, four hydraulic cylinders 5 are fixed and the piston rods 6 of hydraulic cylinders 5 bear a top bed 8 through spherical bearings 7.

A rod 9 with an engaging head 9' runs through top bed 8 and a load-conversion mechanism casing 10 hangs from the bottom of rod 9. Over load-conversion mechanism casing 10 comes an oscillating bed II through which rod 9 runs. Under load-conversion mechanism casing 10 are fitted guides 25, 25 whose lower ends are bent inward and a projection 12' at the top of chucks 12 is held by these guides 25, 25. In the chucks 12, a gap S is left between projection 12' and guide 25 and this makes it possible for the chucks to shift within certain limits relative to the loadconversion mechanism casing 10. Shifting of the chucks is also possible in the direction perpendicular to the paper in FIG. 1.

As evident from the above constitution chucks l2 hang from the top bed 8 vertically slidable. The oil pressure exerted on the rod 6 of the hydraulic cylinder 5 from the top bed 8 causes the chucks to rise.

After the engaging head 9' of the rod 9 touches the top of the top bed 8, all of the oscillating bed 11, the load-conversion mechanism casing 10 and the chucks 12 go up.

The load-conversion mechanism within the casing 10, which mechanically converts the downward thrust exerted by the rod 6 of the hydraulic cylinder 5 upon the top bed 8 (static load) into a dynamic load and transmits this dynamic load to the chucks 12, plays one of the vital roles in the constitution of the present invention. In this load-conversion mechanism. a rod 14 runs through four corners of the top bed 8 and the oscillating bed 11. The upper end of rod 14 terminates as an engaging head 14' and at the lower end of same a roller 15 is rotatably held. It should be noted here that roller 15 and rod 14 are not rigidly fixed to the loadcoversion mechanism casing 10, but held freely movable in a vertical direction to the load-conversion mechanism casing 10. The load-conversion mechanism casing 10 is equipped with a rotatable cam 16 which engages roller 15, cam 16 being driven by the hydraulic motor and gearing provided in the load-conversion mechanism casing 10. Referring to FIG. 3 to explain this arrangement, the hydraulic motor I7 is installed for each cam 16'. and the drive shaft 17' of each hydraulic motor 17 is linked to the camshaft 16' of each cam 16. The gearing 18 of the cam-shaft 16' provided on the opposite side to the hydraulic motor 17 serves to synchronize the rotations of two cam-shafts 16'. The mutually meshing four gears 18 assure that the two cam-shafts 16 rotate all the time in synchronism. The sectional profile of the cam 16 can be anything, so long as it assures that, when the casing I0 is assumed to be stationary, the rotation of the cam 16 at the same time causes the vertical displacements of the roller 15 and the rod I4. Generally, it is recommended, considering the generation of noise and the smooth action of the mechanism. that the cam be given a circular section.

Between the top bed 8 and the oscillating bed 11 there are four strong compression springs 19 inserted and these springs 19 are guided by rod 14.

The chucks 12 of such a type as in the prior art, say, for example the ones in which a pair of rings are opened or closed by the oil pressure, are employed. In the embodiment illustrated in FIG. 4, the hydraulic cylinder 12a is fixed to one of the rings 12b, while the tip of the rod 12a of the hydraulic cylinder 12a is fixed to the other of the rings 12b. The attachment 20 within the rings 12b, 12b, which is exchangeable to suit the profile of a concrete pile, a sheet pile or other pile, serves to hold or release these piles.

it goes without saying that a hole for passing a pile runs through the centers of the top bed 8, the oscillating bed I], the load-conversion mechanism casing 10, the slide bed 4 and the foundation 1.

Driving of a steel sheet pile 21 into the ground by means of this pile driver of the constitution described above is here to be described. The attachment in the chucks 12 is one that matches the profile of the steel sheet pile 2!. First, the pressurized oil is supplied to the hydraulic cylinder 12a of the chucks 12. The steel sheet pile 21 is fixed to the chucks 12. Then the oil is supplied to the hydraulic cylinder 5, thereby causing the rod 6 to apply a downward thrust (static load) on the top bed 8. Thereupon, the downard thrust compresses the compression spring 19 whose force is then transmitted to the chucks 12 or the steel pile 21 via the roller T5 at the lower end of the rod 14, the cam 16 and the load-conversion mechanism casing 10.

When in this state, the hydraulic motor 17 is driven and the cam I6 is rotated, the rotation of the cam 16 causes the compression spring 19 to be compressed and thereby, the downward thrust of the top bed 8 (static load) is converted by the compression spring 19 into a dynamic load, which is then transmitted to the chucks l2 and accordingly to the steel sheet pile 21. Since, in general. the ground is more easily broken by dynamic load than by static load, such an application of dynamic load on the chucks 12 can effect pile driving far faster than an application of only the static load of the hydraulic cylinder 5. Of course, the hydraulic motor 17 may be started from the beginning of pile driving, but when in the beginning of pile driving the pile can go into the ground under the static load of the top bed 8 alone, the hydraulic motor 17 may be resorted to only when the pile driving becomes difficult.

The device illustrated in the present embodiment is remarkably effective in successively driving steel sheet piles 21 with the illustrated sectional profile, Between a steel sheet pile 2i and another steel sheet pile 21 adjacent in the movable direction ofthe foundation 1 by the caterpillar 2, there is a variance of L in the relative position of the chucks. in the conventional device, to compensate for this L variance in the position of chucks the pile driver as a whole has to be shifted, but in the pile driver ofthis invention in which the slide bed 4 is movable along the rails 3, 3 in a direction perpen dicular to the progress of the foundation 1, the foundation I has only to be shifted in its progressive direction and it need not be shifted in a direction perpendicular to this progressive direction. Thus, the work efficiency can be drastically enhanced. The bed 4 is movable along the rails 3, 3, for example, by means of conventional hydraulic power.

When steel sheet piles 21 have to be driven in successively, a new steel sheet pile must be driven along the pile 21 already driven into the ground. in the conventional pile driver, if the first steel sheet pile 21 driven into the ground is slightly inclined to the ground surface, it will be difficult to drive the next pile along this inclined one already driven in.

In the pile driver of the present invention in which the chucks 12 are somewhat shiftable in relation to a load-conversion mechanism casing 10, it is possible to drive a succeeding pile along the already driven one 21 successfully, because the chucks 12 can adapt itself to any variance of angle, which may develop between the pile already driven in and the next one to be driven along the former.

In the above process, the step of dropping the rod 6 of the hydraulic cylinder 5 to the bottom most limit, then releasing the pile from the chucks and switching the hydraulic circuit to raise tht top bed 8 is repeated until the whole length of the pile 21 goes into the ground. In this process, the foundation 1 has to be connected to the stationary part of the structure above the ground surface so that the foundation 1 can be pre' vented from floating during operation.

in the embodiment described above, the cam 16 is provided on the side of the chucks l2 and the compression spring 19 is provided on the side of the top bed 8, but this relationship may be reversed; that is, the cam may come on the side of the top bed and the spring on the side of the chucks. It is recommendable that the rpm of the cam 16 match the natural frequency of the compression spring 19. The invented pile driver is to be driven by a high-low pressure oil pump equipped with a multiple-valve, a pressure control valve, 2 flow-rate control valve, a pressure gauge, etc., but they are not shown here.

The illustrated embodiment of the present invention concerns a case of driving piles in succession. For the purpose to compensate for the variance in the position of the chucks between adjacent piles, the slide bed 4 is made horizontally movable in relation to the foundation 1. Meanwhile, for the purpose to enable the driving of the next pile along the one already driven in, the chucks 12 are substantially designed somewhat shiftable near-horizontally in relation to the top bed 8. Thus, the pile driver of the present invention, when the purpose is to drive concrete piles simply in succession with adequate spacings between them, needs no mechanism for shifting the chucks as described above. Thus, no inconvenience will be felt for that purpose, even if the hydraulic cylinder is placed directly on the foundation and the relative movement between the chucks and the top bed is prohibited.

As described above, the pile driver of the present invention, which mechanically converts the static load of the hydraulic cylinder into a dynamic load and transmits the dynamic load to the chucks holding a pile, can effect pile driving far faster than when only the static load is utilized. As seen from its structure, the present pile driver, being free from noise generation, can prevent a noise pollution in the construction work, which recently has become a social problem.

Moreover, the arrangement in the illustrated embodiment in that the slide bed is made horizontally movable in relation to the foundation; the hydraulic cylinder and the top bed are installed on this slide bed; and the chucks are made shiftable relative to the top bed, is highly useful for successive driving of piles when the relative position of the chucks differs between adjacent piles and along the pile already driven in, a next pile has to be driven.

What is claimed is:

l. A pile driver comprising a foundation and hydraulic cylinder means vertically mounted upon the foundation, a top bed connected to the hydraulic cylinder means adapted to move in a vertical direction upon activation of the hydraulic cylinder means, pile-h0lding chuck means below the top bed and adjustably connected thereto, an oscillating body between the top bed and the chuck means, spring means between the oscil- 4. A pile driver as in claim 3 wherein the direction of bed movement is perpendicular to the direction of movement of the pile driver.

5. A pile driver as in claim 1 wherein the pile-holding chucks are horizontally adjustable relative to the top bed.

6. A pile driver as in claim I wherein the rotatable cam means for compressing the spring means comprises an eccentric cam with a circular section. 

1. A pile driver comprising a foundation and hydraulic cylinder means vertically mounted upon the foundation, a top bed connected to the hydraulic cylinder means adapted to move in a vertical direction upon activation of the hydraulic cylinder means, pileholding chuck means below the top bed and adjustably connected thereto, an oscillating body between the top bed and the chuck means, spring means between the oscillating body and the top bed for deflecting the oscillating body in a downward direction, and rotatable cam means provided on the pile-holding chuck means contacting the oscillating body and sequentially compressing the spring means as the cam means rotates.
 2. A pile driver as in claim 1 wherein the foundation includes means for moving the pile driver in a horizontal direction.
 3. A pile driver as in claim 2 wherein the foundation includes a horizontally slidable bed.
 4. A pile driver as in claim 3 wherein the direction of bed movement is perpendicular to the direction of movement of the pile driver.
 5. A pile driver as in claim 1 wherein the pile-holding chucks are horizontally adjustable relative to the top bed.
 6. A pile driver as in claim 1 wherein the rotatable cam means for compressing the spring means comprises an eccentric cam with a circular section. 